1. Field
The present invention relates to an organic light-emitting display device, a method of manufacturing the same, and a donor substrate and a donor substrate set used to manufacture the organic light-emitting display device.
2. Description of the Related Art
Generally, an organic light-emitting display device includes an anode, a cathode, and organic layers interposed between the anode and the cathode. The organic layers include at least a light-emitting layer and may further include a hole injection layer, a hole transport layer, an electron transport layer and an electron injection layer, in addition to the light-emitting layer. The organic light-emitting display device is classified as a polymer organic light-emitting display device or a small molecule organic light-emitting display device depending on the material that forms the organic layer, particularly, the light-emitting layer.
In order to realize a full-color organic light-emitting display device, it is required to pattern the light-emitting layer. The light-emitting layer may be patterned using a fine metal mask (FMM) in the case of the small molecule organic light-emitting display device and using inkjet printing or laser induced thermal imaging (LITI) in the case of the polymer organic light-emitting display device. Among others, the LITI method has the advantages of finely patterning the organic layer as well as being a dry process instead of a wet process as in the inkjet printing method.
In order to form the pattern of the polymer organic layer using the LITI method, at least a light source, a substrate for an organic light-emitting display device, i.e., a device substrate, and a donor substrate are required. The donor substrate includes a base film, a light-to-heat conversion layer, and a transfer layer composed of an organic layer. The patterning of the organic layer on the device substrate is performed while light emitted from the light source is absorbed into the light-to-heat conversion layer and converted into heat energy. The organic layer composing the transfer layer is transferred onto the device substrate by the heat energy.
Different base films may be used for a donor substrate for forming a green light-emitting layer and a donor substrate for forming a red light-emitting layer. In addition, a buffer layer inserted between the base film of the donor substrate for forming the green light-emitting layer and a transfer layer for forming the green light-emitting layer may be different from a buffer layer inserted between the base film of the donor substrate for forming the red light-emitting layer and a transfer layer for forming the red light-emitting layer. If different base films and buffer layers are used, the number of process variables may increase, and it may be difficult to identify the cause of defects. Furthermore, an organic light-emitting display device manufactured using the LITI method with different base films and buffer layers may have low luminous efficiency and a short lifetime.